1. Field of the Invention
The present invention relates to a suction valve including a valve seat (3), a valve guard (2) and a valve element (4) which is arranged in a reciprocating manner between valve seat (3) and valve guard (2), and further including an unloader (22) having a plurality of fingers (24) which reach through flow passages (13) in the valve seat (3) and which lie against the valve element (4), whereby the unloader (22) is arranged in a non-rotational manner relative to the valve seat (3) and is guided in an axial direction by means of an anti-rotation lock for the unloader.
2. The Prior Art
Suction valves of compressors are often designed with unloaders. Such unloaders essentially serve to start the compressor under no load or to switch the compressor to an idling operation.
To prevent wear of the unloader against the guide element, especially during dry-running of compressors, guide strips and guide rings in the unloader guides have been used for years, as exemplarily shown in EP 686 770 or DE 44 31 512 A1. In addition, rotation of the unloader is limited by the use of stopping blocks 21 made of a synthetic material, as illustrated in FIG. 3. Such stopping blocks 21 are screwed to the valve seat 3 by means of screws 23. Should this prevention against rotation be eliminated, the unloader fingers 14 would rub against the bridges of the passage openings 13 on the valve seat 3 and cause damage to the valve and/or to the unloaders themselves due to the high degree of wear. Based on the many geometric shapes of valve designs, the stopping blocks 21 would have to be additionally made to fit for each valve and be produced and stored in small numbers. Costs caused by this process become correspondingly high. Besides, the stopping blocks 21 can negatively influence the flow conditions in the valve.
It is therefore the object of the present invention to provide an anti-rotation lock and a guide for an unloader of a suction valve which can be generally employed in suction valves of different geometric shapes without negative influences on the functioning of the suction valve.